Gas fired fireplace insert with heat extractor

Abstract

A combination glass door fireplace closure and heat exchanger which can be inserted into the cavity of a gas fired fireplace to permit more efficient and economical operation thereof. The insert includes a plurality of substantially parallel C-shaped exchanger tubes. The lower and upper ends of the tube are coupled to a glass door fireplace closure which is adapted for sealing the frontal opening of the fireplace cavity. A substantially C-shaped heat exchanger duct surrounds the tubes and the lower and upper ends thereof are coupled to the glass door fireplace closure. A gas pipe nozzle is mounted beneath the tubes above the heat exchanger duct and is covered by a quantity of sand supported by a tray. The nozzle pipe is coupled to a gas supply pipe extending from the side of the fireplace. Gas discharged from the pipe diffuses through the sand to produce uniform burning when mixed with air drawn through a combustion air inlet in the glass door fireplace closure. A fan blows air through the heat exchanger tubes. Air flows by convection through the exchanger duct. A first manifold structure permits air to be separately drawn into the heat exchanger tubes, the heat exchanger duct, and into the combustion area through the fireplace closure. A second manifold structure at the top of the fireplace closure couples the upper end of the heat exchanger tubes and the heat exchanger duct so that warm air is expelled therefrom through common air outlets in the fireplace closure.

I claim: 
     
       1. A gas fired heat extractor insert for the cavity of a fireplace, comprising: a plurality of substantially parallel C-shaped heat exchanger tubes having open lower and upper ends;   a substantially C-shaped heat exchanger duct surrounding the tubes and having an open lower end adjacent the lower ends of the tubes and an open upper end adjacent the upper ends of the tubes, the duct extending substantially across the width of the tubes;   a glass door fireplace closure for sealing the frontal opening of the cavity and attached to the ends of the tubes and the duct;   first manifold means for coupling the lower ends of the tubes to a first air inlet extending through the fireplace closure;   conduit means for coupling the lower end of the duct to a second air inlet extending through the fireplace closure;   second manifold means for coupling the upper ends of the tubes and the duct to a plurality of air outlets extending through the fireplace closure, including a plurality of outlet pipes extending between the outlets in the fireplace closure and the upper ends of the tubes and the duct, the pipes being spaced apart to permit hot exhaust gases to rise upwardly therebetween into a flue of the fireplace; and   nozzle means mounted beneath the tubes and above the duct for discharging a combustible gas from a source connectable thereto so that the gas can be burned with air drawn through a third air inlet extending through the fireplace closure.   
     
     
       2. A gas fired heat extractor insert for the cavity of a fireplace, comprising: a plurality of substantially parallel C-shaped heat exchanger tubes having open lower and upper ends;   a substantially C-shaped heat exchanger duct surrounding the tubes and having an open lower end adjacent the lower ends of the tubes and an open upper end adjacent the upper ends of the tubes, the duct extending substantially across the width of the tubes;   a glass door fireplace closure for sealing the cavity and attached to the ends of the tubes and the duct;   first manifold means for coupling the lower ends of the tubes to a first air inlet extending through one side of the lower portion of the fireplace closure, including a fan for blowing air through the tubes;   conduit means for coupling the lower end of the duct to a second air inlet extending through the other side of the lower portion of the fireplace closure;   second manifold means for coupling the upper ends of the tubes and the duct to a plurality of air outlets extending through the fireplace closure and spaced across the upper portion thereof, including a plurality of outlet pipes extending between the outlets and the upper ends of the tubes and the ducts, the pipes being spaced apart to permit hot exhaust gases to rise upwardly therebetween into a flue of the fireplace;   third manifold means for coupling the upper ends of the tubes and the duct to the pipes;   nozzle means mounted beneath the tubes and above the duct for discharging a combustible gas from a source connectable thereto so that the gas can be burned with air drawn through a third air inlet extending through the middle of the lower portion of the fireplace closure, the nozzle means including at least one gas pipe extending substantially perpendicular to the tubes, the pipe having a cap sealing its one end, a coupling at its other end for coupling the pipe to a gas supply pipe, and a plurality of longitudinally spaced holes extending through the sidewall of the gas pipe and directed generally downwardly;   a tray mounted beneath the gas pipe of the nozzle means and above the duct; and   a quantity of sand filling the tray and covering the gas pipe of the nozzle means for diffusing the combustible gas discharged from the gas pipe.   
     
     
       3. The invention of claim 2 and further comprising a plurality of rocks supported by the tray and intermixed with the sand.